Photocurable liquid polyene-polythiol polymer composition

ABSTRACT

THE INVENTION DISCLOSED IS FOR A NEW PHOTOCURABLE LIQUID POLYMER COMPOSITION WHICH INCLUDES A LIQUID POLYENE COMPONENT HAVING A MOLECULE CONTAINING AT LEAST TWO UNSATURATED CARBON-TO-CARBON BONDS DISPOSED AT TERMINAL POSITIONS ON A MAIN CHAIN OF THE MOLECULE, A POLYTHIOL COMPONENT HAVING A MOLECULE CONTAINING A MULTIPLICITY OF PENDANT OR TERMINALLY POSITIONED -SH FUNCTIONAL GROUPS PER AVERAGE MOLEULE, AND A PHOTOCURING RATE ACCELERATOR. THE PHOTOCURABLE LIQUID POLYMER COMPOSITION UPON CURING IN THE PRESCENE OF THE ACTINIC LIGHT FORMS ODORLESS, SOLID, ELASTOMERTIC OR RESINOUS PRODUCTS WHICH MAY SERVE AS SEALANTS, COATINGS, ADHESIVES AND MOLDED ARTICLES.

United States Patent 3,697,396 PHOTOCURABLE LIQUID POLYENE-POLYTHIOLPOLYMER COMPOSITION Clifton L. Kehr, Silver Spring, and Walter R.Wszolelr, Sykesville, Md., assignors to W. R. Grace & Co., New York,N.Y.

No Drawing. Division of application Ser. No. 44,607, June 8, 1970, nowPatent No. 3,661,744, which is a continuation-in-part of applicationSer. No. 617,801, Feb. 23, 1967, now abandoned, which in turn is acontinuation-impart of application Ser. No. 567,841, July 26, 1966, nowabandoned. This application June 25, 1971, Ser. No. 156,976

Int. Cl. C08d 1/00; C08f I/16; C084: 11/54 US. Cl. 204-15914 17 ClaimsABSTRACT OF THE DISCLOSURE The invention disclosed is for a newphotocurable liquid polymer composition which includes a liquid polyenecomponent having a molecule containing at least two unsaturatedcarbon-to-carbon bonds disposed at terminal positions on a main chain ofthe molecule, a polythiol component having a molecule containing amultiplicity of pendant or terminally positioned --SH functional groupsper average molecule, and a photocuring rate accelerator. Thephotocurable liquid polymer composition upon curing in the presence ofactinic light forms odorless, solid, elastomeric or resinous productswhich may serve as sealants, coatings, adhesives and molded articles.

The present application for US. Letters Patent is a divisional of Ser.No. 44,607, filed June 8, 1970, now Pat. No. 3,661,744, issued May 9,1972, which in turn is a continuation-in-part of copending applicationSer. No. 617,801, filed Feb. 23, 1967, now abandoned, which in turn is acontinuation-in-part of application Ser. No. 567,- 841, filed July 26,1966, now abandoned.

This invention relates to a new high energy curable liquid compositionwhich includes a liquid polyene component having a molecule containingat least two unset-- urated carbon-to-carbon bonds disposed at terminalpositions on a main chain of the molecule, a polythiol component havinga molecule containing a multiplicity of pendant or terminally positionedSH functional groups per average molecule, and a photo-curing rateaccelerator.

It is well known in the art that cure of internally unsaturated polymerssuch as polybutadiene or polyisoprene may be eifected with polythiols.However, such polymers, due mainly to residual internal unsaturationafter curing, are unstable either to thermal oxidation or ultra-violetcatalyzed oxidation, and are subject to rapid attack by ozone.Eventually degradation and embrittlement results in the internal doublebond polymers, substantially reducing their useful service life.

A limitation of commercially available liquid polyurethane prepolymersis the fact that they are terminated by isocyanate (NCO) groups. These--NCO groups are extremely unstable in storage, and are highlywater-sensitive such that under practical conditions, they react withtraces of moisture from the atmosphere to form gaseous carbon dioxideand amino groupings which in turn react with more -NCO to formeventually a highly viscous, sometimes completely insolubleurea-extended chain network. In cases where insolubilization occurs, thepolymer has to be discarded at great expense. Further, if the-NCO-terminated prepolymers come in contact with traces of either acidicor basic impurities, dimerization and/ or trimerization of the --NCOfunctions may take place to form viscous, sometimes insoluble productsduring storage. Even mild alkalis such as those constituents normallypresent on the surface of glass vessels and containers may cause storageproblems.

A further limitation for some applications is found in polyurethanepolymers of the prior art which are derived from aromatic diisocyanatesor polyisocyanates such as tolylene-2,4-diisocyanate,tolylene-2,6-diisocyanate, 4,4- diisocyanatodiphenylmethane, and thelike. These aromatic diisocyanates (or mixtures thereof) enjoyWidespread use in polyurethane elastomers, foams, and coatings, becauseof their ready commercial availability, high degree of reactivity andrelatively low cost. The derived polyurethane products, however, areknown to turn yellow, amber, orange or brown in color when exposed tosunlight, ultraviolet light or other forms of actinic radiation. Thisyellowing tendency imparts a definite limitation on the usage of suchpolyurethanes in many applications. There is evidence in the technicalliterature that shows that this yellowing or discoloration problem isdirectly attributable to the aromatic (benzeneoid) nucleus in thearomatic diisocyanates, and accordingly serious yellowing problems inpolyurethanes may be avoided by use of aliphatic polyisocyanates such ashexamethylene diisocyanate. These aliphatic polyisocyanates, however,are diflicult to manufacture, are relatively expensive and arerelatively slow in reaction rate during polymer formation reactions incomparison to the aromatic polyisocyanates.

The use of polymeric liquid polythiol polymers which are cured to solidelastomeric products by oxidative coupling of the thiol (SH) groups todisulfides (SS groups) are known in the sealants, coatings and adhesivesfield. Oxidizing agents such as Pb0 are commonly used to effect thiscuring reaction. These mercapto-contalmng compounds, however, bothbefore and after curing with PbO -type curing system yield elastomericcompositions with an offensive odor which limits their usefulnessgenerally to outdoor service. Thus, oxidatively-cured mercapto polymersystems have found restricted commercial acceptance due to theiroifensive odors.

A limitation of commercial liquid polymeric sealants and coatings isfound in one-package systems. All the compound ingredients, includingthe curing agents, are blended together and charged into a tightlysealed container until used. In these commercial sealants (polysulfides,polydisulfides, polymercaptans, polyurethanes and polysilicones), thecuring reaction of one-package systems is initiated by moisture (H O)from the air. The moisture-curable systems leave something to be desiredbecause the moisture content of the air varies widely. Hence, the curingperformance of moisture-curable adhesives, coatings and sealants isvariable and is difiicult to predict and control. In the case ofpolyurethanes a further disadvantage of moisture-curable systems isobserved. In the curing reaction (NCO groups reacting with H O) avolatile gas (carbon dioxide) is liberated and this evolved gas tends tocause unsightly and propertyweakening gas pockets or voids in the finalproduct.

It has now been found that numerous defects of the prior art may beeffectively overcome by practice of the present invention which provides,a new photocurable liquid composition containing particular polyeneswhich are curable by polythiols to solid resins or elastomers. Forexample, when urethane-containing polyenes are compounded withpolythiols, the prepared composition may be stored safely for longperiods of time in the absence of actinic light. Upon exposure toactinic light such as ultraviolet light, the prepared system may becured rapidly and controllably to a polythioether-polyurethane productwhich is low in cost and equal or better in reaction rate in polymerformation when compared with compositions derived from conventionaltechnology.

Generally stated, the present invention provides a photocurablecomposition which comprises a particular polyene component, a polythiolcomponent, and a photocuring rate accelerator.

The polyene component may be represented by the formula:

bit

wherein m is an integer of at least 2, wherein X is a member selectedfrom the group consisting of:

C=C-R Lil In the groups (a) to (e), f is an integer from 1 to 9; R is aradical selected from the group consisting of hydrogen, fluorine,chlorine, furyl, thienyl, pyridyl, phenyl and substituted phenyl, benzyland substituted benzyl, alkyl, and substituted alkyl, alkoxy andsubstituted alkoxy, and cycloalkyl and substituted cycloalkyl. Thesubstituents on the substituted members are selected from the groupconsisting of nitro, chloro, fiuoro,-acetoxy, acetamide, phenyl, benzyl,alkyl alkoxy and cycloalkyl. Alkyl and alkoxy have from 1 to 9 carbonatoms and cycloalkyl has from 3 to 8 carbon atoms.

The members (a) to (e) are connected to [A] through divalent chemicallycompatible derivative members. The members (a) to (e) may be connectedto [A] through a divalent chemically compatible derivative member of thegroupconsisting of Si(R) carbonate, carboxylate, sulfone, O-

alkyl and substituted alkyl, cycloalkyl and substituted cycloalkyl,urethane and substituted urethane, urea and substituted urea, amideandrsubstituted amide, amine and substituted amine, and arylandsubstituted aryl. Thealkyl members have from 1 to 9 carbon atoms, thearyl members are either phenyl or naphthyl, and the cycloalkyl membershave from 3 to 8 carbon atoms with R and said members substituted beingdefined above. B is a member of the group consisting --O-, S, and NR--.

The member [A] is polyvalent; free of reactive carbon-to-carbonunsaturation; free of highly water-sensitive members; and consisting ofatoms selected fromthe group consisting of carbon, oxygen, nitrogen,chlorine, bromine, fluorine, phosphorus, silicon and hydrogen.

The polyene component has a molecular weight in the range from about 64to 20,000, preferably about 200 to about 10,000; and a viscosity in therange from essentially 0 to 20 million centipoises at C. as measured bya Brookfield Viscometer.

The polythiol component has a molecularweight in the rangefrom about 50to about 20,000 and the general formula:

wherein j and k are integers greater than 1; R is a member of the groupconsisting of hydrogen, and alkyl having 1 to 9 carbon atoms; R is amember of the group consisting of hydrogen, and saturated alkyl having 1to 9 carbon atoms; R, is a divalent derivative of the group consistingof phenyl, benzyl, alkyl, cycloalkyl, substituted phenyl, substitutedbenzyl, substituted alkyl and substituted cycloalkyl; with the termsalkyl, cycloalkyl and members substituted being defined above.

General representative formulas for the polyenes of the; presentinvention may be prepared as exemplified I e ow:

EDlfunctlonal Trifunctional tletrafunctional Interconnected-modifieddlfunctional Interconnected-modified tetrafunctional 7Interconnected-modified difunctional III. POLY (ALKYLENE-ETHER) POLYOLRE- ACTED WITH POLYISOCYANATE AND UNSAT- URATED MONOALOOHOL FORMINGPOLY- URETHANE POLYENES AND RELATED POLY- MERS DifunctionalTrifuuctional In the above formulas, the sum of x+y+z in each chainsegment is at least 1; P is an integer of l or more; q is at least2; nis at least .1; R is selected from the group consisting of hydrogen,phenyl, benzyl, alkyl, cycloalkyl, and substituted phenyl; and R is amember of the group consisting of CH HCH 7? hydrogen, phenyl,cycloalkyl, and alkyl.

The novel class of polyenes of this invention derived from carbon tocarbon unsaturated monoisocyanates may be characterized by extreme caseand versatility of manufacture when theJiquid functionality desired isgreater than about three. For example, consider an attempted synthesisof a polyhexene starting with an -OH terminatedpolyalkylene ether hexolsuch as Niax Hexol LS-490 (Union Carbide Corp.) having a molecularWeight of approximately 700, and a viscosity of 18,720 cps. at C. Anattempt to terminate this polymer with ene groups by reacting onemolesof hexol with 6 moles of tolylenev diisocyanate (mixed-2,4-,-2-6-isomer product) and 6 moles of allyl alcohol proceeded nicely butresulted in a prematurely chain extended and crossiinked solid productrather than an intended liquid polyhexene. Using the monoisocyanateroute, however, this premature chain extension may be avoided and thedesired polyurethane-containing liquid polyhexene may be very easilyprepared by a simple, one-step reaction of one mole-of hexol with 6moles of allyl isocyanate. This latter polyhexene has the addedadvantage of being cured using the teachings of this invention to anon-yellowing polythioetherpolyurethane product. Similarly, theunsaturated monoisocyanate technique may be used to prepare liquidpolyenes from other analagous highly functional polyols such ascellulose, polyvinyl alcohol, partially hydrolized polyvinyl acetate,and the like, and highly functional polyamines such as tetraethylenepentamine, polyethyleneimine, and the like.

A general method of forming one type of polyene containing urethanegroups is to react a polyol of the general formula Baron wherein R is apolyvalent organic moiety free from reactive carbon-to-carbonunsaturation and n is at least 2; with a polyisocyanate of the generalformula Ru NCO).

wherein R is a polyvalent organic moiety free from reactivecarbon-to-carbon unsaturation and n is at least 2 and a member of thegroup consisting of an ene-ol, yne-ol, ene-arnine and yne-amine. Thereaction is carried out in an inert moisture-free atmosphere (nitrogenblanket) at atmospheric pressure at a temperature in the range from O toabout C. for a period of about 5 minutes to about 25 hours. In the casewhere an ene- 01 or yne-ol is employed, the reaction is preferably a onestep reaction wherein all the reactants are charged together. In thecase where an ene-amine or yne-amine is used, the reaction is preferablya two step reaction wherein the polyol and the polyisocyanate arereacted together and thereafter preferably at room temperature, thecue-amine or yne-amine is added to the NCO terminated polymer formed.The group consisting of ene-ol, yne-ol, ene-amine and yne-amine areusually added to the reaction in an amount such that there is onecarbonto-carbon unsaturation in the group member per hydroxyl groupin'the polyol and said polyol and group member are added in combinationin a stoichiometric amount necessary to react with the isocyanate groupsin the polyisocyanate.

A second general method of forming a polyene containing urethane groups(or urea groups) is to react a polyol (or polyamine) with ancue-isocyanate or an yneisocyanate to form the corresponding polyene.The general procedure and stoichiometry of this synthesis route issimilar to that described for polyisocyanate in the preceding. In thisinstance, a polyol reacts with an ene-isocyanate to form thecorresponding polyene. It is found,

however, that products derived from this route, when cured in thepresence of an active light source and a polythiol, may form relativelyweak solid polythioether products. To obtain stronger cured products, itis desirable to provide polar functional groupings within the main chainbackbone of the polymeric polyene. These polar functional groupingsserve as connecting linkages between wherein R is a polyvalent organicmoiety free from reactive carbon-to-carbon unsaturation and n-is atleast 2; with either an ene-ol or yne-ol. The reaction is carried out inan inert moisture-free atmosphere (nitrogen blank-- et) at atmosphericpressure at a temperature in the range from to about 120 C. for a periodof minutes to 25 hours. Usually the reaction is carried out in thepresence of a catalyst (p-toluene sulfonic acid) and in the presence ofa solvent, e.g. benzene at refluxing temperature. The'water formedisazeotroped off of the reaction.

Another method of making an ester containing polyene is to react apolyol of the formula and the like are generally not desirable withinthe scope of this invention. These activated ene compounds are veryprone to self-polymerization reactions to form vinyl polymers. Excessiveamounts of self-polymerization of the ene groups is an undesirable sidereaction in the present invention since the desired polythioetherreaction products are precluded whenever self-polymerization of the enegroups occurs. Finally, the presence of activated, easilyself-polymerizable ene groups in the composition leads to oxygeninhibition during curing, storage stabil ity problems, or the need forexcessively high inhibitor concentrations.

In formingv the urethane-containing polyenes of the present invention,catalytic amounts of a catalyst may be employed to speed up thereaction. This is especially true in the case Where an ene-o1 is used toform the polyene. Such catalysts are well known to those in the art andinclude organometallic compounds such as stannous octoate, stannousoleate, dibutyl tin dilaurate, cobalt acetylacetonate, ferricacetylacetonate, lead naphthanate and dibutyl tin diacetate. I

In summary, by admixing polyenes or polyynes containing two or morereactive unsaturated carbon-to-carbon bonds located terminal from themain chain with a polythiol containing two or more thiol groups permolecule and thereafter exposing said liquid mixture having photocuringrate accelerator to actinic light, there is provided an essentiallyodorless solid elastomeric or resinous polymeric product.

Polythiol as used herein refers to 'simple'or complex organic compoundshaving a multiplicity of pendant or terminally positioned -SH functionalgroups per average molecule. a a

On the average the polythiol must contain 2 or more -SH groups/moleculeand have a viscosity range of essentially 0 to 20 million centipoises(cps.) at 70 C. as measured by a Brookfield Viscorneter either alone orwhen in the presence of an inert solvent, aqueous dispersion orplasticizer. Operable polythiols in the instant invention usually havemolecular weights in'the range about 50 to about 20,000, and preferablyfrom about 100 to about 10,000.

The polythiols operable in the instant invention may be exemplified bythe general formula where n is at least 2 and R is a polyvalent organicmoiety free from reactive carbon-to-carbon unsaturation. Thus R maycontain cyclic groupings and hetero atoms such as N, P or O andprimarily contains carbon-carbon, carbon-hydrogen, carbon-oxygen, orsilicon-oxygen contain- 10 ing chain linkages free of any reactivecarbon-to-carbon unsaturation.

One class of polythiols operable with polyenes to obtain essentiallyodorless polythioether products are esters of thiol-containing acids ofthe formula HS--R COOH where R is an organic moiety containing noreactive carbon-to-carbon unsaturation with polyhydroxy compounds ofstructure wherein R is an organic moiety containing no reactivecarbon-to-carbon unsaturation, and n is 2 or greater. These componentswill react under suitable conditions to give a polythiol having thegeneral structure:

where R and R are organic moieties containing no reactivecarbon-to-carbon unsaturation, and n is 2 or greater.

Certain polythiols such as the aliphatic monomeric polythiols, ethanedithiol, hexamethylene dithiol, decamethylene dithiol,tolylene-2,4-dithiol, and the like, and some polymeric polythiols suchas a thiol-terminated ethylcyclohexyl dimercaptan polymer, and the like,and similar polythiols which are conveniently and ordinarily synthesizedon a commercial basis, although having obnoxious odors, are operable butmany of the end products are not widely accepted from a practical,commercial point of view. Examples of the polythiol compounds preferredbecause of relatively low odor level include but are not limited toesters of thioglycolic acid u-mercaptopropionic acid (HSCH(CH )COOH andB-mercaptopropionic acid (HS-CH2CH2COCH) with polyhydroxy compounds suchas glycols, triols, tetraols, pentaols, hexaols, and the like. Specificexamples of the preferred polythiols include but are not limited toethylene glycol bis (thioglycolate), ethylene glycol bis(ti-mercaptopropionate), trimethylolpropane tris (thioglycolate),

trimethylolpropane tris (,B-mercaptopropionate), pentaerythritoltetrakis (thioglycolate) and pentaerythritol tetrakis(B-mercaptopropionate), all of which are commercially available. Aspecific example of a preferred polymeric polythiol is polypropyleneether glycol bis ([3- mercaptopropionate) which is prepared frompolypropylene-ether glycol (e.g. Pluracol P2010, Wyandotte ChemicalCorp.) and l3-mercaptopropionic acid by esterification.

The preferred polythiol compounds are characterized by a low level ofmercaptan-like odor initially, and after reaction, give essentiallyodorless polythioether end products which are commercially attractiveand practically useful resins or elastomers for both indoor and outdoorapplications.

Prior to curing, the curable liquid polymer may be formulated for use assolids, or disposed in organic solvents, or as dispersions or emulsionsin aqueous media.

The curable liquid polymer compositions prior to curing may readily bepumped, poured, siphoned, brushed, sprayed, doctored, or otherwisehandled as desired. Following application, curing in place to a solidresin or elastomer may be efiected either very rapidly or extremelyslowly as desired by manipulation of the compounding ingredients and themethod of curing.

The liquid polythioether-forming components and compositions, prior tocuring, may be admixed with or blended with other monomeric andpolymeric materials such as thermoplastic resins, elastomers orthermosetting resin monomeric or polymeric compositions. The resultingblend may be subjected to conditions for curing or cocuring of thevarious components of the blend to give cured products having unusualphysical properties.

Although the mechanism of the curing reaction is not completelyunderstood, it appears most likely that the curing reaction may beinitiated by most any actinic light source which dissociates orabstracts a hydrogen atom from an SH group, or accomplishes theequivalent thereof. Generally the rate of the curing reaction may beincreased by increasing the temperature of the composition at the timeof initiation of cure. In many applications, however, the curing isaccomplished conveniently and economically by operating at ordinary roomtemperature conditions. Thus for use in elastomeric sealants, it ispossible merely to photoexpose the polyene, polythiol, photocuring rateaccelerator admixture to ambient conditions andpobtaina photocured solidelastomeric. or resinous product.

By proper choice of type and concentration of photocuring rateaccelerator forv initiation, the curing period required for conversionof the polyene/polythiol composition from the liquid to the solid statemay be varied greatly as desired. In combination, with suitableaccelerators or retarders, .the curing period may vary from about asecond or, less to about 30 days or more. In general, short curingperiods are achieved in applications where thin films of curablecomposition are required, such as in the field of coatings whereas thelong curing periods are achieved and desired where more massive layersof composition are required, such as in the field of elastomericsealants.

A class of actinic light useful herein is ultraviolet light and otherforms of actinic radiation which are normally found in radiation emittedfrom the sun or from artificial sources such as Type RS Sunlamps, carbonarc lamps, xenon arc lamps, mercury vapor lamps, tungsten halide lampsand the like. Ultraviolet radiation may be used most efiiciently if thephotocura ble polyene/polythiol composition contains a suitablephotocuring rate accelerator. Curing periods may be adjusted to be veryshort and hence commercially economical by proper choice of ultravioletsource, photocuring rate accelerator and concentration thereof,temperature and molecular weight, and reactive group functionality ofthe polyene and polythiol. Curing periods of less than about 1 secondduration are possible, especially in thin filmapplications such asdesired for example in coatings and adhesives.

Conventional curing inhibitors or retarders which may be used in orderto stabilize the components or curable compositions so as to preventpremature onset of curing may include hydroquinone; p-tert.-butylcatechol; 2,6-ditert.-butyl-p-methylphenol; phenothiazine; N phenyl 2-naphthylamine; inert gas atmospheres such as helium, argon, nitrogen andcarbon dioxide; vacuum; and the like.

It is understood to be within the scope of this invention that thephotocuring rate accelerator may be present as a separate and distinctcomponent such as azobenzene, as a mixture of two or more separatecomponents, such as benzophenone; benzanthrone; anthrone, anddibenzosuberone; carbon tetrachloride and phenanthrene; and the like, orin a chemically combined form within the molecularstructure of eitherthe polyene or the polythiol. An example of this latter conditionwherein the photocuring rate accelerator is present not as a separatecomponent, but rather in a form chemically combined within the polyenecomponent is the following structure which contains four reactivecarbon-to-carbon unsaturated groupings and one diaryl ketone groupingsper average molecule:

Specifically useful herein are chemical photocuring rate acceleratorssuch as benzophenone, acetophenone, acenapthene-quionone, o-methoxybenzophenone, Thioxanthen-9-one, xanthen-9-one, 7-H-Benz [de]anthracen-7- one, dibenzosuberone, l-napththaldehyde, 4,4'-bis(dimethylamino) benzophenone, fiuorene-9-one, 1'acetonaphthone,2'-acetonaphthone, anthraquinone, l-indanone, 2-tert.-butylanthraquinone, valerophenone, hexanophenone, S-phenylbutyrophenone,p-mor pholinopropiophenone, 4-morpholinobenzophenone,4'-morpholinodeoxybenzoin, ,p-diacetylbenzene, 4-aminobenzophenone,4'-methoxyacetophenone, benzaldehyde, u-tetralone, 9-acetylphenanthrene,2-acetylphenanthrene, lo-thioxanthenone, 3-acetylphenanthrene,3-acetylindole 1,3,5-triacetylbenzene, and the like including blendsthereof, to greatly reduce the exposure times.

The curing rate accelerators are usually added in an amount ranging fromabout 0.0005 to about 50% by Weight of the photocurable composition,with a preferred range being from about 0.05 to about 25% by weight.Preferred photocuring rate accelerators are the aldehyde and ketonecarbonyl compounds having at least one aromatic nucleus attacheddirectly to the group.

To obtain the maximum strength, solvent resistance,

creep resistance, heat resistance and freedom from tackiness, thereaction components consisting of the polyenes and polythiols of thisinvention are formulated in such a manner as to give solid, crosslinked,three dimensional network polythioether polymer systems on curing. Inorder to achieve such infinite network formation the individual polyenesand polythiols must have a functionality of at least 2 and the sum ofthe functionalities ofthe polyene and polythiol components must alwaysbe greater than 4. Blends and mixtures of the polyenes and thepolythiols containing said functionality are also operable here- Thecompositions to be cured, i.e., (converted to solid resins orelastomers) in accord with the present invention may, if desired,include such additives as antioxidants, accelerators, dyes, inhibitors,activators, fillers, pigments, anti-static agents, flame-retardantagents thickeners, thixotropic agents, surface-active agents, viscositymodifiers, extending oils, plasticizers, tackifiers and the like withinthe scope of this invention. Such additives are usually preblended withthe polyene or polythiol prior to or during the compounding step.Operable fillers include natural and synthetic resins, carbon black,glass fibers, wood flour, clay, silica, alumina, carbonates, oxides,hydroxides, silicates, glass flakes, glass beads, borates, phosphates,diatomaceous earth, talc, kaolin, barium sulfate, calcium sulfate,calcium carbonate, antimony oxide and the like. The aforesaid additivesmay be present in quantities up to 500 parts or more per parts polymerby weight and preferably about 0.005 to about 300 parts on the samebasis.

The compounding of the components prior to curing may be carried outinseveral ways. For example, the polyene, the polythiol and any otheradditives may be admixed and charged to an aerosol can, drum, tube, orcartridge for subsequent use.

Another useful method of compounding isto prepare in an ambientatmosphere by conventional mixing techniques but in the absence ofactinic radiation on a composition consisting of polyene, antioxidant(to inhibit spontaneous oxygen-initiated curing), polythiol, UVsensitizer or photoinitiator, and other inert additives. Thiscomposition may be stored in the dark for extended periods of time, buton exposure to actinic radiation (e.g., ultraviolet light, sunlight,etc.) will cure controllably and in a very short time period to solidpolythioether products.

The mole ratio of ene/thiol groups for preparing the curable compositionis from about 0.2/1 to about 5/1, and desirably about .75/ 1 to about1.5/1 group ratio.

The following examples will aid in explaining, but should not be deemedas limiting, the instant invention. In the cases, unless otherwisenoted, all parts and percentages are by weight.

FORMATION OF POLYENE PREPOLYMER Example 1 458 g. (0.23 mole) of acommercially available liquid polymeric diisocyanate solid under thetrade name Adiprene L-100 by E. I. du Pont de Nemours & Co. was chargedto a dry resin kettle maintained under a nitrogen atmosphere andequipped with a condenser, stirrer, thermometer, and gas inlet andoutlet. 37.8 g. (0.65 mole) of allyl alcohol was charged to the kettleand the reaction was continued for 17 hours with stirring at 100 C.Thereafter the nitrogen atmosphere was removed and the kettle wasevacuated 8 hours at 100 C. 50 cc. dry benzene was added to the kettleand the reaction product Was azeotroped with benzene to remove theunreacted alcohol. This allyl terminated liquid prepolymer had amolecular Weight of approximately 2100 and will be referred to asPrepolymer A hereinafter.

Example 2 400 g. (0.2 mole) of Adiprene Ll was charged to a dry resinkettle maintained under nitrogen and equipped with a condenser, stirrer,thermometer and gas inlet and outlet. 25.2 g. (0.43 mole) of propargylalcohol (HCECCH2OH) was added to the kettle and the reaction wascontinued with stirring for 18 hours at 160 C. Thereafter the nitrogenatmosphere was removed and the kettle was evacuated 16 hours at 100 C.followed by azetotropic distillations with 50 cc. water and then 50 cc.benzene to remove any excess propargyl alcohol. This HCEC- terminatedliquid prepolymer had a viscosity of 27,500 centipoises at 70 C. and amolecular weight of 2100 and will be referred to as Prepolymer Bhereinafter.

Example 3 1 mole of commercially available poly(ethylene ether) glycolhaving a molecular weight of 1450 and a specific gravity of 1.21 wascharged to a resin kettle maintained under nitrogen and equipped with acondenser, stirrer, thermometer and a gas inlet and outlet. 2.9 g.dibutyl tin dilaurate as a catalyst was charged to the kettle along with2 moles tolylene-2,4-diisocyanate and 2 moles of allyl alcohol. Thereaction was continued with stirring at 60 C. for 2 hours. Thereafter avacuum of 1 mm. was applied for 2 hours at 60 C. to remove the excessalcohol. This CH =CH terminated prepolymer had a molecular weight ofapproximately 1950 and will hereinafter be referred to as Prepolymer C.

Example 4 1 mole of a commercially available polypropylene ether) glycolhaving a molecular weight of about 1958 and a hydroxyl number of 57.6was charged to a resin kettle equipped with a condenser, stirrer,thermometer and a gas inlet and outlet. 4 g. of dibutyl tin dilaurate asa catalyst was added to the kettle along with 348 g. (2.0 moles) oftolylene-2,4-diisocyanate and 116 g. (2 moles) of allyl alcohol. Thereaction was carried out for 20 minutes at room temperature undernitrogen. Excess alcohol was stripped from the reaction kettle by vacuumover a 1 hour period. The thus formed CH =CH terminated liquidprepolymer had a molecular weight of approximately 2400 and willhereinafter be referred to as Prepolymer D.

Example 5 750 g. of a N-containing tetrol (hydroxyl functionality=4)available from Wyandotte Chemicals Corp. under the trade name TetronicPolyol 904 having a 14 M.W. of 7,500 was placed in a reaction vesselheated at 110 C. The flask was maintained under vacuum for 1 hour. Then,under an atmosphere of nitrogen, 0.1 cc. dibutyl tin dilaurate was addedand the flask was cooled to 50 C. Now 18.3 g. allyl isocyanate was addedslowly, maintaining the temperature at about C. for about 1 hour afterthe addition was completed. The thus formed polymeric polyene (i.e.,Prepolymer E hereinafter) had a theoretical allyl functionality of 2.2,a theoretical hydroxyl functionality of 1.8, and a calculated molecularweight of about 7,683.

Example 6 To a resin kettle maintained under a nitrogen atmosphere andequipped with a condenser, stirrer, thermometer and gas inlet and outletwas added 843 g. of a commercially available liquid diisocyanateprepolymer sold under the trade name Multrathane F-196 by Mobay ChemicalCo., said prepolymer having a molecular weight of about 1680 and anavailable isocyanate content of 4.7-5.2%. 87 g. (1.5 moles) of allylalcohol was added to the kettle and the reaction was continued for 18hours at 140 C. with stirring. Thereafter the nitrogen atmosphere wasremoved and the kettle was evacuated for 22 hours at C. 50 cc. of drybenzene was added to the kettle and the reaction product was azeotropedtherewith to remove any unreacted alcohol. This CHFCH- terminated liquidprepolymer had a viscosity of 25,000 centipoises at 70 C. and amolecular weight of approximately 1800 and will be referred to asPrepolymer F hereinafter.

Example 7 678 g. (0.34 mole) of a commercially available poly (propyleneether) glycol sold under the trade name NIAX by Union Carbide Co. andhaving a molecular weight of about 2025 was degassed for 2 hours at 100C. and thereafter charged to a resin kettle maintained under a nitrogenatmosphere and equipped with a condenser, stirrer, thermometer and gasinlet and outlet. 118 g. (0.68 mole) of tolylene 2,4-diisocyanate wascharged to the kettle and the reaction was heated with stirring for 2%hours at 120 C. After cooling, 58 g. (1.0 mole) of allyl alcohol wasadded to the kettle and the mixture was refluxed at 120 C. for 16 hoursunder nitrogen. Excess allyl alcohol was removed overnight by vacuum at100 C. Half of the allyl terminated. liquid prepolymer having aviscosity of 19,400 cps. at 30 C. as measured on a viscosity of 19,400cps. at 30 C. as measured on a Brookfield Viscometer was removed fromthe kettle and will be referred to hereinafter as Prepolymer G. Theother half portion of the prepolymer was combined with 50 cc. of drybenzene and azeotroped overnight following which excess benzene waspulled out under vacuum for 5 hours at 120 C. This portion of theallyl-terminated liquid prepolymer had a viscosity of 15,600 cps. at 70C. as measured on a Brookfield Viscometer and a molecular weight ofapproximately 2500 and will hereinafter be referred to as Prepolymer H.

Example 8 751 g. (0.38 mole) of a commercially avaiable poly (propyleneether) glycol sold under the trade name Pluracol P 2010 by WyandotteChemical Co. was degassed at room temperature for 3 hours and thencharged to a dry resin kettle maintained under a nitrogen atmosphere andequipped with a condenser, stirrer, thermometer and gas inlet andoutlet. 132 g. (0.76 mole) of tolylene-2,4-diisocyanate was charged tothe kettle and the kettle was heated for 2 hours at 120 C. with stirringunder nitrogen. After cooling 58 g. (1.0 mole) of allyl alcohol wasadded and the mixture was refluxed at 120 C. overnight. Excess allylalcohol was stripped by vacuum overnight at 120 C. The thus formed allylterminated liquid prepolymer had a viscosity of 15,000 cps. as measuredon a Brookfield Viscometer at 70 C. and a molecular weight ofapproximately 2500 and will hereinafter be referred to as he polymer I.

Example 9 To a 1 liter resin kettle equipped with stirrer, thermometer,gas inlet and outlet and heated to a temperature of 50 C. was charged610 g. (0.2 mole) of poly(tetramethylene ether)glycol, commerciallyavailable from Quaker Oats Co. and having a hydroxyl number of 37.1along with 0.3 g. dibutyl tin dilaurate. The temperature of the kettlewas raised to 110 C. and the contents were freed of water underlmillimeter vacuum for 1 hour. The resin kettle was cooled to 60 C. andthe system was placed under a protective atmosphere of nitrogenthroughout the remainder of the reaction. 25.2 g. of allyl isocyanate(0.4 mole) was added dropwise to the kettle at such a rate as tomaintain the temperature at 60 C. When the NCO content dropped to 0.54mg./g., 1 mm. vacuum again was applied and the system was heated at 70C. for one hour. The thus formed polymer product was a solid at roomtemperature but at 50 C. is clear and pourable. The polymer product hada viscosity of 1,800 centipoises at 70 C. as measured on a BrookfieldViscometer and an average molecular weight of approximately 3200.

Example 10 To a 1 liter resin kettle equipped with stirrer, thermometer,gas inlet and outlet was charged 591 g. (0.30 mole) of a poly(propyleneether) glycol commercially available from Union Carbide under the tradename PPG 2025. and 0.3 g. of dibutyl tin dilaurate. The kettle washeated to 110 C. and the contents were freed of water under 1 mm. vacuumfor 1 hour. The kettle wascooled to 25 C. and the system was placedunder a protective atmosphere of nitrogen throughout the remainder ofthe reaction. 53.1 ml. (49.8 g., 0.6 mole) of allyl isoclyanatecommercially available from Chemetron Corp. was added to the system. Anexotherm carried the temperature to 45 C. in 22 minutes. After 60minutes, the NCO content (as determined by titration) was 0.04 mg./g.The system was placed under 1 mm. vacuum and heated to 70 C. to removetraces of unreacted allyl isocyanate. The resultant polymer product had.a viscosity of 600 centipoises at 30 C. as measured on a BrookfieldViscometer and an average molecular weight of approximately 2200.

The next two examples show a method of preparing the polyenes of theinstant invention by dehydration of polyether glycols.

Example 11 100 g. of poly(propylene ether) glycolcommercially availablefrom Union Carbide under the trade name PPG 2025 was poured through ahot tube filled with aluminum oxide at such a rate that the entirereaction took place in 2 hours. The tube was 1 in diameter with thereaction zone 1 ft. long and completely enclosed within a tube furnace.The alumina catalyst was 10-18 mesh and was maintained at 350 C. using aLindberg Hevi- Duty tube furnace. The tube was fitted with a droppingfunnel and a nitrogen inlet at the top. Nitrogen pressure was kept onthe system throughout the reaction. The product collected from thebottom of the tube was analyzed for. unsaturation by the mercuricacetate titration method and was found to have 100% of the theoreticalamount of unsaturttion expected after dehydration of both therminalhydroxyl groups of the poly(propylene ether) glycol. The polyene producthad a viscosity of 125 cps. at 70 C. and an average molecular weight ofapproximately 2000.

Example 12 1 kilogram of poly(propylene ether) glycol commerciallyavailable from'Union Carbide under the trade name PPG 2025 was heated to120 C. in a round bottom flask. To this was added 120 ml. excess) ofacetic anhydride at such a rate that the temperature of the mixture waskept at 120-140 C. Following the addition, the mixture was heated at 140C. for 4 hours. It was then cooled and diluted with an equal volume ofchloroform, washed with 10% aqueous sodium carbonate, then with water.The organic layer was separated and the chloroform was removed bydistillation. Infrared analysis of the purified material showed it to bethe diacetate of the poly(propylene ether) glycol with no residualhydroxyl groups.

g. of this diacetate was put through the hot tube as in Example 11except that the packing was glass helices instead of alumina and thetemperature was 375 C. The product contained 64% of the theoreticalamount of unsaturation expected after the elimination of acetic acidfrom both terminal acetoxy groups of the poly- (propylene ether) glycoldiacetate.

Example 13 114 g. of hexol sold under the trade name NIIAX Polyol LS-490by Union Carbide Chemicals Co. having a. molecular weight of 684 wascharged to a 1 liter 4 neck flask and heated to C. under vacuum andnitrogen for 1 hour. It was then cooled to approximately 60 C. whereat0.1 cc. of dibutyl tin dilaurate was added followed by slowly adding 83g. (1 mole) of allyl isocyanate to keep the temperature in the range7080 C. during the addition. After addition, the reaction was allowed tocontinue for 1 hour at 70 C. The polymeric hexaene product obtained hadan average molecular weight of approximately 1200 and a viscosity of 300centipoises at 70 C.

Example 14 Example 15 To a 1 liter 4 neck flask was charged 100 cc. ofdi-v methylformamide, 100 g. of tolylene-2,4-diisocyanate and 0.1 cc.dibutyl tin dilaurate. 58 g. of hexol, i.e. NIAX Polyol LS-490 by UnionCarbide and 34 g. of allyl alcohol were mixed together and added.dropwise to the flask. Before the addition to the flask was completed,the reaction, which was exothermic, gelled and the addition wasdiscontinued.

A comparison of Examples 13, 14 and 15 shows that Example 13 is animprovement over Examples 14 and 15 in that it allows one to formpolymer without the necessity of a solvent. A comparison of Examples 14and 15 shows that when starting with a highly functional polyol usingthe diisocyanate/allyl alcohol technique one must operate in dilutesolution to avoid premature crosslinking (i.e., gelation) which rendersthe polyene product useless as a curable liquid prepolymer. This problemis avoided completely by using the unsaturated monoisocyanate techniqueillustrated in Example 13.

Example 16 In a 1 liter, 4 neck flask 220 g. of hexol commerciallyavailable from Union Carbide Chemicals Co. under the trade name NIAXPolyol LS-490 (0.32 mole) and 0.1 cc. of dibutyl tin dilaurate washeated to 110 C. under vacuum for 1 hour. After cooling in nitrogen toapproximately 60 C., 80 g. of allyl isoclyanate was added to the flaskby means of a dropping funnel. The exothermic reaction produced atemperature of 100 C. approximately C. and with nitrogen passingthrough, When the addition was complete the reaction was com a mixtureof 10 g. of allyl alcohol and g. of tolylenetinued at C. for 1 hour. Theresulting triene poly- 2,4-diisocyanate was added 'via a dropping funnelat a mer product had an average molecular weight of approximoderaterate. The reaction was allowed to continue for mately 950 and aviscosity of 300 centipoises as measured 5 15 minutes. A maximumtemperature of C. was onaBrookfield Viscometer at 70 C. produced by theexothermic reaction. The polymeric Example 17 product obtained was aSOlld at room temperature but l1qu1d at 70 C. The product had an averagemolecular To a 1 liter 4 neck fl was charged 300 gof a p yweight ofapproximately 10,500 and a viscosity of 270,000 ester diol (molecularweight 3232) sold under the trade 10 centipoises at 70 C. name RCPolyester S 101-35; b317, R.(ll. Diwgflion, HooIkgr E l 19 ChemicalCorp. and 0.1 cc. 0 di uty tin auratc. e F 11 h d f Ex 1 12 d flask washeated to C. of dibutyl tin dilaurate. The 0 owmg t e pmce 0 amp 6 anusmg flask was heated to C. under vacuum and maintained necessary g aPolyene of the followmg formula thereat for 1 hour. The flask was cooledto approximately 15 was prepare 60 C., nitrogen was admitted, and 7.7 g.allyl isocyanate C H O-(C H 0) -C H and 8.1 g. oftolylene-2,4-diisocyanate was added by Example 20 means of a droppingfunnel to the reaction at a moderate Following the procedure of Example3, and using rate. A maximum temperature of 90 C. was needed. When theaddition was complete the reaction was allowed 20 necessary mutants 3 Py 0f the followlng formula to continue at 70 C. for 1 hour. The thusformed solid Was Prep re cm on,

0 0 o o HCEC-Cm-O-iLNH NH- 0-(0,Hto)tti -NH NH -&

0 o HCEC-OlL-O-PJ-NH NH-ii-O-(ChHtO),

polymeric product had an average molecular weight of Example 21approximately 6800 and a vlscosliy of ceimpolses A crotyl-terminatedpolyurethane which contains two when measured onaBmokfield Vlscometer at70 40 reactive double bonds per average molecule in a near Example 18terlminal polszition was3pr%ared folltlowing lthe general1 promg poymenc po yene To a 1 liter 4 neck flask heated at 110 C. was charged 060 Xamp e e .resu 808 g. of a polyester diol (having a molecular weightwas found to havc the followmg formula 3232) sold under the trade nameRC Polyester S 101-35 Example 22 by RC. Division Hooker Chemical Corp.and 0.1 cc. Following the procedure of Example 3, and using dibutyl tindilaurate. The flask was maintained under vac, necessary reactants, apolyene of the following formula uum at 110 C. for 1 hour. The flask wascooled to was prepared:

OOJH.

338 m m 09 :82 fiuoaewneifi nm 0oz gammy 53o8-5335 &. a l I. memo "wasom mo mofioomo mo v mu 5E0 mm 0 7 3208" Q 655 82558: oe fioi mvqm. 2 @91H v w2o8n wm: 4w zobm kewaegeaoiwfi 6208a B QBQ- fiofig gnaw t t 0oz HHOHHO AW HO. MO HHO w VmOlON 450 m mo H M BSQEO HE u e flenv HE v eb Z aum 5 w w m w m n m w w w m t .6 s I e b w OXEHOV O wW HHZ NZ MW O -mO UONO O O 0 NZ H 1 Example 23 I I Following the procedure of Example 3 andusing necessary reactants, a polyeneuof the followingfformula wasprepared: v

Examples 24-42 Following the general procedure of the prior examples,and using the necessary reactants, a series of polyenes having theformula: X(-BA-} BX where gz, ,is 1 qr,, .v greater were'preparedwherein the denva'tive niem forming the polyenes are defined in thefollowing:

27 Example 45 0.005 mole of the allyl-terminated liquid Prepolymer E wascharged to a 2 oz. glass jar along with a stoichiometric amount of apolythiol to react with the allyl groups 28 2 hours at 120 C. withstirring under nitrogen. Thereafter, 116.9 g. (2 moles) of allyl alcoholwas added to: the kettle and the mixture was refluxed for 16 hours at:120 C. Excess allyl alcohol was stripped by vacuum at in Prepolymer B,0.0036 mole of trimethylolpropane tris 11.50 for 23 hours Thethus'formed I teri (fi-mercaptopropionte), and 2% total weight ofbenzopolyene Prepolymer had mqlecular welght: of: phenone. The liquidreactants were stirred together approximately 24604500 scoslty of106,000 fl briefly at room temperature and allowed to stand under asmeasured on fli' tlilfi c vlscgmeter at 30 (3.1 1 ambient conditions.After exposure to ultraviolet light, 0005 0 e f orfne q yg a solid,odorless, self-supporting, cured elastomeric polywere charg to a 2 g assP a 9 thioethm. polymer resultei I metric amount of the polymericdithlol prepared in EX-1 ample 65. 0.5 g. of acetophenone (a UVphotoinitiator) p 46 was charged to the glass jar and the mixture wasimmedi- Example 45 was repeated except that 0027 mole f ately stirred.Thereafter the mixture was placed outdoors} pentaerythritol tetrakis(B-mercaptopropionte) was subcurmg- 24 hours a 5011i self'suppol'tlng,stituted for the trimethylolpropane tris s-mercaptoproit 1658: 91111341elasilc P y resultedpionatrcgl.1 Aftlertphotocuririgtgcutiifd solid,odorlesst, sielf- Example 60 e as omeric 0 we er 0 mer resu e i 1 suppoy p y 4.5 g. (0.02 mole) diallyl adlpate was charged to :1; Example 47 22 oz. glass bottle along with a stoichiometric amount of? 0.005 mole ofthe HCEC- terminated liquid Prepolyp to react with the H2= H- groups ithe mer B was charged to a 2 oz. glass jar along with a dlallyi p smole) of pentaerythlltolf stoichiometric amount to react with the*I-ICEC groups L tetra'kls (fl- P R 9P and of f -i in Prepolymer B oftrimethylolpropane tris (fl-mercaptophenone (a UV sensitizer). Thereactants were stirredv propionate) (0.0033 mole), and 2% total weightof briefly and then placed outdoors 1D. the sunlight atamblbenzophenone. The reactants were stirred together and ellt pp g.$0116, after photoexposure to. ultraviolet light, a cured vsolid,polythloethel P y resulted In s ha 3 minute-5.} odorless,self-supporting, elastomeric polythioether polyp I mer resulted. 1Exampl? 61 j,

E l 48 Example 60 was repeated except that-0.02 mole of dillyl phthalatewas substituted for the diallyl adipate. 0.005 mole of thealll-termmated h u1d Pre l mer a 1"v was charged to a 2 02? glass jar alongwith a ggi hio- A self'supportmg Sohd .odorless cured Polythloetherl,metric amount to reactwith the allyl groups of the Pre- Polymer productresulted m less than 1 hour '1 polymer, i.e. 0.0033 mole oftrimethylolpropane tris ()8- Example 62 mercaptopropionte) having amolecular weight of 398, I I and 2% total weight of benzophenone. Theliquid re- Example.6o was except that 9' actants were stirred together.Thereafter the reactants dlauyl et was sPbsmuted for the dlauyl f werephotocured under ambient conditions. The reactants self'supportmgz sohdm' cured pQlythloether formed a solid, odorless, self-supporting, curedelastomeric 4 Product resulted m 30 mmutes' polythioether polymer. Exam1 63 The following examples in Table I show curing by ultraviolet light.In all the examples in Table I, 10 g. f was "'P f P that P; i; of theallyl-terminated liquid polyene prepolymers were zzjdlanyloxypropane YsuPstltuted for the dlanyll charged toanopen glass jar to which wasad'dedastoichio- 1 ad 1Pate- A self'supportmg: solld, oflorlessi cured PY" metric {amount of a polythiol necessary to react with the thioetherpolymer. product resulted in less than 1 hour allyl groups of theprepolymer and any UV sensitizer" Example 64 l or activator employed.The reactants were stirred briefly E 0 and then placed outdoors forindirect photoexposure to H1016) y a1111116 was charged to the sunlight.Examples were checked periodically to de- 50 2 oz. glass bottle alongwith a stoichiometric amount of termine the extent ofcure. j polythiolto react with the vinyl groups in the diallylj TABLE I 1 I PolyenePolyene: UV ac Example prepolythlol, UV celerator; Curing No. polymerPolythiol moleratio accelerator (g) observations G P-33 Cured to anodorless solid in 4 wks. G Q43 Cured to an odorless solid in 1 wk. GQ-43 0.2 Do. G Q-43 1:0.5 o 0.2 Cured to anodorless solidinlday. G Q-431:0. 5 Methyl ethyl ketone... 0. 2 Cured to an odorless solid in 4 days.H Q,-43 1:0.5 Aceto henone... 0.5, Cured inlhr. H Q-43 1:0.5 Cycloexanone 0.5 Cured ln3hrs. H P-33 1:0.5 Acetophenone- 0.5' Cured inlhr. IQ43 1:0.5 do 0.5 Cured to an odorless solid in 15 minutes. I Q-43 1:0. 6---do 0.5 No cure in 19 hrs. in dark room. f

l P-33=Trlmethylolpropane tris (fl-mercaptopropionate);Q-43==Pentaerythritol tetrakis (fl-mercaptopropionate).

Example 59 1510 g. of a commercially available polyoxypropylene glycolsold under the trade name Pluracol P 2010 by Wyandotte Chemical Corp.was charged to a resin kettle maintained under a nitrogen atmosphere andequipped E with a condenser, stirrer, thermometer and gas inlet and 7outdoors in the sunlight under atmospheric conditions. i

outlet. The reactant was degassed at room temperature spectively soldunder the trade name -Mondur TD was charged to the kettle and the kettlewas heated for amine; i.e. 4.9 g. (0.01 mole); of pentaerythritoltetrakisg (fl-mercaptopropionate) and 0.5 g. acetophenone (a UV;activator). The reactants were stirredbriefly and placed In less than 15minutes a self-supporting, solid, odorless, cured, clear, rubberypolythioether polymer resulted. i

The following shows another example of the curing of I a polymericthio-containing compound and a vinyl-termi-E nated polymer.

29 Example 65 1.5 moles of fl-mercaptopropionic acid, 0.5 moles of acommercially available poly(propylene ether) glycol sold under the tradename Pluracol P-2010 by Wyandotte Chemical Corp. and 0.1 g.p-toluenesulfonic acid and 50 ml. benzene were charged to a resin kettlemaintained under a nitrogen atmosphere and equipped with a condenser,stirrer, thermometer and gas inlet and outlet. The mixture was heatedand the benzene-water azeotrope was collected. The actual amount ofwater collected amounted to 17.5 g. The reaction was vacuum-stripped forseveral hours at 70 C. to remove benzene. The resulting polythiolpolymer had a molecular weight of about 2210- 2230 and an averagefunctionality of 2 and was collected for use herein.

659 g. (0.145 mole of a poly(propylene ether) triol commerciallyavailable from Wyandotte Chemical Corp. under the trade name PluracolTPE 4542 having a molecular weight of about 4500 and a hydroxyl numberof 37.1, and 0.3 g. of dibutyl tin dilaurate were charged to a resinkettle maintained under a nitrogen atmosphere and equipped with acondenser, stirrer, thermometer and gas inlet and outlet. The reactantswere maintained at 110 C. for 1 hour and then cooled under nitrogen toroom temperature. 25.2 g. (0.435 mole) of allyl alcohol was added to thekettle followed by 75.7 g. (0.435 mole) of an 80-20% isomer mixture oftolylene-2,4-diisocyanate and tolylene 2,6-diisocyanate respectivelysold under the trade name Mondur TD 80. The temperature reached 55 C. in6 minutes. A sample was titrated for NCO resulting in 6.02 mg. NCO/g.after 20 minutes. After 1 hour the NCO titration showed 0.997 mg. NCO/g. The polyene polymer had a molecular weight of about 5200 and anaverage functionality of 3 and was vacuum stripped at 70 C. for 1 hourand then collected. 0.003 mole of the polythiol polymeric materialformed supra were charged to a 2 oz. glass jar along with 0.002 mole ofthe allyl-terminated polyene polymer formed herein and 0.5 g.acetophenone. The reactants were stirred briefly and then placedoutdoors under atmospheric conditions. In /2 hour a self-supporting,solid, odorless, clear, cured polythioether polymer product resulted.

Example 66 3 g. of a linear saturated hydrocarbon backboneethylene/propyleneMon-conjugated diene terpolymer commercially availableunder the the trade name Nordel by E. I. du Pont de Nemours Co. whichhad been visbroken until it had a reduced specific viscosity of 0.99 andcontained 0.4 vinyl, 6.4 trans and 0.4 vinylidene unsaturated groups per1000 carbon atoms, was dissolved in 100 ml. of benzene in a glass jar. A50% excess over the stoichiometric amount, i.e. 0.0006 mole (0.3 g.) ofpentaerythritol tetrakis ([i-mercaptopropionate) was added to the jar inaddition to 0.5 g. acetophenone. The glass jar was placed in thesunlight outdoors under atmospheric conditions. After 24 hours thebenzene had substantially evaporated leaving a gelatinous polymericprecipitate. Acetone was added to precipitate more polymer. The polymerwas filtered off, washed with acetone and dried in a vacuum oven at 60C.

2.3 g. of the above polythioether polymer product was extracted withbenzene along with a control sample of the starting visbroken Nordelmaterial. The control sample showed a gel content (benzene insoluble) of3.4% whereas the cured (crosslinked) solid polythioether polymer producthad a gel content of 82.8%.

Example 67 0.5 mole of a carboxyl-terminated polyisobutylene,commercially available from Enjay Chemical Co. having a molecular weightof about 1800, 0.1 g. of p-toluenesulfonic acid catalyst, 1.5 moles ofallyl alcohol were charged to a resin kettle maintained under a nitrogenatmosphere and equipped with a condenser, stirrer, thermometer and gasinlet and outlet. The mixture was heated at reflux for 2 hours, then 50ml. benzene added and the benzene-water azeotrope was collected. Theactual amount of water collected amounted to 17.5 g. The reaction wasvacuum stripped for several hours at 70 C. to remove benzene and anyunreacted allyl alcohol.

0.005 mole of the thus formed polyene (9.6 g.), 0.0025 mole (1.2 g.) ofpentaerythritol tetrakis (fl-mercaptopropionate) and 0.5 g. ofacetophenone were charged to a 2 oz. glass jar and briefly stirred. Thejar was placed out-doors under ambient conditions. After /2 hour, aself-supporting, solid, odorless, cured elastomeric product resulted.

'Example 68 643 g. (0.32 mole) of a commercially available poly-(propylene ether) glycol sold under the trade name Pluracol P 2010 byWyandotte Chemical Co. was degassed at room temperature for 1 hour andthen charged to a resin kettle maintained under a nitrogen atmosphereand equipped with a condenser, stirrer, thermometer and gas inlet andoutlet. 111.4 g. (0.64 mole) of a -20% isomer mixture oftolylene-2,4-diisocyanate and tolylene- 2,6-diisocyanate respectivelysold under the trade name Mondur TD 80 was added to the kettle. After 45minutes, the temperature was raised to C. and the reaction was continuedfor 50 minutes. A sample was removed and titrated for NCO resulting in33.54 mg. NCO/g. 62.7 g. of diallyl amine was added at 105 C. and thereaction was continued for 10 minutes. A sample was titrated resultingin an NCO content of 1.20 milligrams NCO/g. A vacuum was applied to thekettle for 1 hour at 90 C. followed by cooling under nitrogen. Theresulting product had a molecular weight of about 2540-2580 and an enefunctionality of 4.

10 g. of the thus formed polymer was charged to a 2 oz. glass jar alongwith 2 g. of pentaerythritol tetrakis (fi-mercaptopropionate) and 0.5 g.acetophenone. The liquid reactants were briefly stirred together andplaced out-doors under ambient conditions. Within 15 minutes a solid,odorless, elastomeric cured polythioether product was obtained.

Example 69 215 g. of poly(ethylene imine) commercially available fromDow Chemical Co. under the trade name Montre-k 18 along with 41.5 g.allyl isocyanate was charged to a resin kettle maintained under anitrogen atmosphere and equipped with a condenser, stirrer, thermometerand gas inlet and outlet. The reactants were maintained at 70 to 80 C.during addition. The reaction was continued for 1 hour at 70 C.

10 g. of the thus formed polymer were charged to a 2 oz. glass jar alongwith 1.5 g. of pentaerythritol tetrakis (p-mercaptopropionate) and 0.5g. of acetophenone. The mixture ws briefly stirred and placed outdoorsin the sunlight at ambient conditions. Within 2 hours a solid,self-supporting, odorless, cured polymer product was formed.

The example was repeated using g. of poly(ethylene imine) and 29.1 g. ofallyl isocyanate under the same conditions and procedure. 10 g. of thispolyene product was reacted with 2.1 g. of pentaerythritol tetrakis(fimercaptopropionate) and 5 g. of acetophenone. The mixture was brieflystirred and placed outdoors in the sunlight at ambient conditions.Within 2 hours a solid, selfsupporting, odorless, cured polymer productwas formed.

Example 70 The polymeric polythiol (0.003 moles, f=2) from Example 65was admixed with a stoichiometric amount (0.002 mole, f=3) of amonomeric polyene, glycerol trioleate (triolein, molecular weight 885)and 0.5 g. acetophenone. The jar containing the reactants after mixingwas placed in the sunlight under ambient conditions. Within /2 hour theliquid mixture was converted to a self-supporting, solid, odorless,clear-rubbery cured poly- 400 g. (0.20 mole) of a commercially availableliquid polymeric diisocyanate sold under the trade name Adiprene L400 by'E. I. du Pont de Nemours & Co. was charged to a dry resin kettlemaintained under a nitrogen atmosphere and equipped Wtih a condenser,stirrer, thermometer and gas inlet and outlet. 25.2 g. (0.45 mole) ofpropargyl alcohol was charged to the kettle and the reaction wascontinued for 17 hours with stirring at 100 C. Thereafter the nitrogenatmosphere was removed and the kettle was evacuated 15 hours at 100 C.

g. of the propargyl terminated liquid prepolymer, 3.0 g. ofpentaerythritol tetrakis (B-mercaptopropionate) and 0.5 g. acetophenonewere admixed together in a 2 oz. glass jar, stirred briefly and placedoutdoors under ambient conditions. Within 2 /2 hours a solid, odorless,selfsupporting, cured elastomeric polymer product resulted.

Example 72 40 g. of Prepolymer I and 10 g. of a filler sold commerciallyunder the trade name Hi Sil 233 by Columbia Southern Chemical Corp. werecharged under nitrogen to a 200 m1. round bottom 3 necked flaskmaintained under a nitrogen atmosphere and mixed thoroughly. The flaskwas heated by a water bath to 60 C. under full vacuum for 2 hours. Theflask was then allowed to cool under vacuum. 4 g. of pentaerythritoltetrakis (fl-merrcaptopropionate) was charged to the flask undernitrogen and the reaction was stirred continuously. The reaction wasthen exposed to ultraviolet light from the atmosphere outdoors and asolid, cured, odorless elastomeric product resulted within minutes.

Example 73 125 g. of Prepolymer E from Example 5 herein was charged to aErlenmeyer flask equipped with a magnetic stirrer and connected bytubing to another Erlenmeyer flask containing 54 g. oftrimethylolpropane tris (fimercaptopropionate). The system was evacuated(0.05 mm.) while heating the polymer to 100 C. with stirring. After 2hours all bubbling ceased. An additional /2 hour evacuation wasperformed. Thereafter the trimethylolpropane tris(fl-mercaptopropionate)was poured into the flask containing Prepolymer E under nitrogen. Afterstirring to insure good mixing, heat was removed and the reaction. wascontinued under nitrogen for 4 days. No

3 ml. of benzene containing 0.5% based on the weight of the prepolymerof an antioxidant solid under the trade name Santonox commericallyavailable from Monsanto Chemical Co. To another of the jars containingPrepolymer E was added 3 ml. of benzene containing 0.5% based on theweight of the prepolymer of an antioxidant sold under the trade nameDalpac FG commercially available from Hercules Powder Co. To the thirdjar was added 3 ml. of benzene as a control. To blend the components thejars were heated in a forced draft oven set at 150 C. for 25 minuteswith frequent stirring. The" jars were withdrawn from the oven and 1.3g. of tri-. methylolpropane tris (fl-mercaptopropionate) was added toeach of the jars and curing was initiated indoors under ambientconditions. The control run, without any antioxidant present, curedwithin /2 hour to a solid elastomeric polymer product. The examplecontaining Dalpac FG cured to a solid polymer product after 12 dayswhereas the sample containing Santonox required more than 2 weeks beforea solid self-supporting, cured polymeric product resulted. v

The polyenes used in the instant invention may be used as blends ormixtures of monoenes or polyenes having the same or differentfunctionalities so long as the average functionality of the blend ormixture is at least 2. Similarly, the polythiols used herein may be usedas blends or mixtures of monothiols or polythiols having the same ordifferent functionalities as long as the average function,- ality of theblend or mixture is at least 2.

The polyene/polythiol mole ratio is selected so as to provide a solidfinal cured product, i.e., one that is nonflowing and structurallyself-supporting under ambient conditions. In typical cases, as shown bythe examples, this ratio can be about 0.2 to 5 moles thiol groups permole ene groups. In general the mole ratios significantly above or belowI tend to give a high proportionof chain extension or grafting whereasmole ratios near 1 give predominantly chain extension and crosslinking.Occasionally, however, ratios necessary to give a solid as aforesaid maylie outside the stated range, and experimentation may be necessary todetermine a suitable ratio to give a' solid. This experimentation iseasily carried out, and offers no difliculties to those skilled in theart.

The following Examples 75-80 show the ability to use mixtures of thepolythiols and how to empirically determine the amount of polythiolnecessary to form cured solid self supporting polymeric products by theinstant invention.

As shown in Examples 75-80, 30 g. of Prepolymer I from Example 8 wereadmixed with varying ratios of a mixture of polythiols and cured byultraviolet light in the presence of acetophenone as a UVphotoinitiator.

Polythiolmixture Aceto- Outdoor Curing Self- Polyene phenone curing timeShoreA support Example No. polymer Q4;3(g.) E-23 (g.) (g.) site (mine)hardness structure 2.9 0 p 0.5 X 7 40 Yes. 2.3 0.6 0.5 X 7 25 Yes 1.71.2 0.5 X 9% 21 Yes. 1.2 1.7 0.5 X 9% 7 Yes. 0.6 2.3 0.5 X 52% 0 Yes:

l Polyene Prepolymer I from Example 8. 2 Q43=pentaerythntol tetrakis (Bmereaptopropionate) commercially available from Carlisle Chemical IE23=ethylene glycol bis (5 mercaptopropionate); No cure.

curing was observed. A sample of the unreacted material was removed fromthe Erlenmeyer flask under nitrogen and placed in a 2 oz. jar. Thesample was exposed to ambient conditions outdoors and in about 2 minutesevidence of curing (viscosity change) was observed. Within 15 minutes,an odorless, solid elastomeric, cured polymer product was obtained,under UV light,

Example 74 10 g. ofvPrepolymer E from Example S was added to each ofthree '2 oz. jars. To one of the jars was added Pentaerythritol tetrakis(mercaptopropionate) .I

The above formulations were briefly admixed for homogeneity andthereafter air cured indoors. Formulation I cured in approximately 6hours to an elastomeric sealant whereas Formulation II cured in two daysto an elastomeric sealant. Curing was accomplished more rapidly when thesamples were placed outdoors in sunlight after mixing.

Example 82 10 g. of Prepolymer D were charged to a 2 oz. glass jar alongwith 0.7 g. of ethylene glycol bis (mercaptopropionate), 2.2 g.pentaerythritol tetrakis (mercaptopropionate), and 0.5 g. benzophenone.The reactants were briefly stirred and then placed between two pieces ofglass plate each of 5 mil thickness. The glass plates were pressedtogether by hand to insure good adhesion, and then exposed to a Type RSSunlamp at a surface radiation intensity of 4000 microwatts/am. for fiveminutes. An attempt was made to pull the glass plates apart. The glassbroke before the adhesive was destroyed.

Example 83 50 g. of Prepolymer H along with 5.0 g. of pentaerythritoltetrakis (mercaptopropionate), and 0.5g. of benzophenone were stirredtogether briefly in a glass jar and then poured into an aluminum mold inthe shape of a shallow dish. The mold was photocured by the procedure ofExample 82 after which the mold was torn away from the molded articlewhich set to a solid in the exact shape of the mold.

" Example 84 0.005 mole of Prepolymer E from Example 5 was charged to a2 oz. glass jar along with 0.0033 mole of trimethylolpropane tn's(fi-mercaptopropionate) and 0.5 g. of acetophenone. The reactants werestirred briefly and then coated on to a piece of 17 pt. clay coatedpaper by means of a No. rod. The paper was then placed outdoors in thesunlight. After 10 mins. a clear solid coating resulted on the paper.The same technique was used successfully to coat cellophane, aluminumfoil, steel plate stock, Mylar polyester film, plywood, and a concreteblock of the type used in building construction.

Example 85 20 g. of the polymeric product from Example 9 was mixed with2.2 g. of pentaerythritol tetrakis (B-mercaptopropionate) commerciallyavailable from Carlisle Chemical Co. under the trade name Q43 and 0.5 g.of acetophenone in a 2 oz. aluminum tray, stirred briefly and cured byirradiating with ultraviolet light from a Sylvania sun lamp. Within 4minutes a solid, odorless, elastomeric product resulted.

Example 86 20 g. of the polymeric product from Example 10 was A similarpolymer. prepared from PPG-2025, tolyl-' ene-2,4-diisocyanate and allylalcohol, cured with pentaerythritol tetrakis ('fl-mercaptopropionate)and acetophenone by irradiation, with ultraviolet light also had aGardner color of less than 1. However, after 47.2 hours in theFadeometer the Gardner color rose to 13.

Example 87 10.25 g. of the polymeric product front l-Example 13 and 6.35g. of pentaerythritol tetrakis (fi -niercaptopro- 34 pionate) were.admixed along with 0.4 g. acetophenone in a beaker. A film approximately.035 inch thick (4.5 inch square) was spread on a glass plate and curedby irradiating it for 5 minutes with ultraviolet light from aWestinghouse sun lamp 8 to 10 inches above the film. The resultant curedproduct had a tensile strength of 368 p.s.i. and an elongation atfailure of 27%. Its Shore A hardness was to 85.

Example 88 10 g. of the polymer product from Example 18 was melted and10 g. of solvent (equal volumes of toluene and 2-ethoxyethyl acetate)was added to lower the viscosity of the melt. To this solution was added0.35 g. of pentaerythritol tetrakis (,8-mercaptopropionate) The solutionwas mixed and a 0.035 inch sheet was cast and irradiated for 3-0 minuteswith a Westinghouse sun lamp. The resultant, clear, cured productcrystallized slowly to a white opaque material which had a tensilestrength of 6310 p.s.i. and an elongation at failure of 720%. It had aShore A hardness of over 100.

Example 89 6 g. of glycerol trioleate (Armour Industrial Chemical Co.)and 2.4 g. of pentaerythritol tetrakis (fl-mercaptopropionate) weredissolved in an ethanolbenzene solution and placed in an aluminum tray.1.0. g. of acetophenone was added and admixed and the mixture wasexposed to the ultraviolet rays of the sun for 3 days. A cured solidfilm was formed in 3 days.

Example 90 10.6 g. of decaglycerol dioleate (Drew Chemical Corp.) and2.0 g. of pentaerythritol tetrakis (B-mercaptopropionate) were dissolvedin ethanol, 1.0 g. of acetophenone was admixed therewith and the mixturein an aluminum tray was placed outdoors in the sunlight. After 3 days acured film was formed.

Example 91 5.6 g. of decaglycerol decaoleate (Drew Chemical Corp.) and2.0 g. of pentaerythritol tetrakis (p-mercaptopropionate) were admixedin an ethylene-benzene solutron in an aluminum tray. 1.0 g. ofacetophenone was added to the mixture and the mixture was placed in thesunlight. After 3 days a cured film resulted.

Example 92 5.2 g. of decaglycerol dioleate (Drew Chemical Corp.) and 2.0g. of ethylene glycol bis (B-mercaptopropionate) were dissolved inethanol in an aluminum tray. 1.0 g. of acetophenone was added to themixture and the mixture was placed in the sun. After 3 days the producthad not solidified to a crosslinked network.

Example 94 94.5 g. of dimer acid commercially available from EmeryIndustries Inc. under the trade name Empol 1010 and 103.5 g. of allylalcohol were admixed in benzene in a 2 neck flask. The reaction 'washeated gently for 19 hours at 80 C. at which time it was determined bytitration that less than 6% of the carboxyl group con- "tentwasunreacted. The reaction was discontinued and the reactants werewashed with water. The thus formed emulsion was salted out thoroughly,the benzene layer was separated and dried to remove residual moisture.The

benzene was distilled oil in vacuum to obtain the diallyl ester ofdimeracid.

The diallyl ester of the dimer acid product was admixed with *Q-43 in a1:1 mole ratio and 1.0 g. acetophenonein an aluminum tray and cured inthe sun. After 2 hours a cured solid product resulted.

The curing example was repeated except that the mole ratio of thediallyl ester of dimer acid to Q-43 was 2: 1. The cured product washarder than the product obtained under the 1:1 mole ratio of diallylester to Q- 43.

14g. of dimer acid, 6 g. of pentaerythritol tetrakis(fl-mercaptopropionate) and 1.0 g. of acetophenone were mixed in analuminum tray. The mixture was placed in the sun. After 22 hours theproduct had not solidified to a crosslinked network.

sultingfrom the'instant invention have many and varied uses. Examples ofsome uses include but .are not limited to adhesives; caulks; elastomericsealants; coatings, encapsulating or potting compounds; liquid castableelastomers; thermoset resins; impregnants for fabric cloth, fibrous websand other porous substrates; laminating adhesives and coatings; mastics;glazing compounds; fiberglass reinforced composites; sizing or surfacefinishing agents, filleting compounds, cure in place gasketing com-vpounds; rocket fuel binders; foamable thermosetting resins orelastomers; molded articles such as gaskets, diaphragms, balloons,automobile tires, etc.

The molecular weight of the polyenes of the present invention may bemeasured by various conventional methods, including solution viscosity,osmoticpressure and gel permeation chromatography. Additionally, the,

EXAMPLES 95-117 UV thrucure rate, Shore A Sample Photocurlng l Poly mihardness Number Polyene Source of Polyene rate accelerator thiol 2minute UV cure 95. 1,2, t-trivinylcyclohexane Aldrich Chem. Co., Inc.-.Benzophenone Q-43 23.3 70 96. 1 o-hexadiene .do. Q-43 35.0 60 97. iallylterephthalate- Chemicals Procurement Lab. Inc- Q-43 -21. 60 98 Diallyloxalate Monomer-Polymer Labs., Inc"-.. Q-43 5. 0 80 99 Diallyl 1,4-cyclohexane-dicarboxylate .do Q43 3. 0 70 1oo Tetraallyl orthosilicateAldrich Chem. 00., Inc Q-43 8. 8 60 101-. Chemicals Procurement Lab.Inc- Q43 43. 7 75 102.- Aldrich Chem. 00., Inc. Q43 17. 90 03 K. dz K.Laboratories, Inc Q-43 11. 7 70 Aldrich Chem. 00., Inc Q-43 7. 0 59Monomer-Polymer Labs., In Q-43 4. 4 75 a ne. 106 Trlallyl cyanurateAldrich Chemical Co Dibenzosuberone P-33 7.0 35 1074-vinyl-1-cyclohexene K. & K. Laboratories, Inc Benzophenone Q-43 1.6 70

Diethyleneglycol divinyl ether (.9 108 e). Polysciences, IncDibenzosuberone Q-43 v 36. 6 42 iallyl amine 1 mole). Monomer-PolymerLabs, Inc- Triallyl phosphate- Aldrich Chemical 00., Inc-.. 10. 0 20 110Diallyl carbonate- Chemical Proc. Labs., Inc 125. 0 63 111 N, N-diallylpipers/I -do 25. 0 57 112 Allyl diglyco carbonate CR-39 from PPG Ind.Inc.- do Q43 100. 0 62 113 Polymeric diene Example 9Tri(o-tolyl)phosphine Q-43 5 20 114 --do ..d0 C014 (15 parts/100) plusQ-43 5 phenanthrene. 1 1 5 (in .dn o-Methoxyphenyl- Q43 10 20 methylketone. 116--.. do o-ll\ ieghoxybenzalde- Q-43 10 20 y e. v

117 an C014 parts/100) Q43 1 3 1 Concentration of photocuring rateaccelerator varied from 0.2 to 1.5 parts/100 parts photocurablecomposition.

1 Q-43 is pentaerythritol tetrakis (fi-mercaptopropionate); reticalequivalent amount based on the polyene used.

P-33 is trlmethylolpropane tris (B-mercaptopropionate) The polythiol isused in thetheo- I Sample thickness ranged from to 140 mils; UV sourcewas a 275 watt Type RS sun lamp; incident radiation intensity at surfaceof photocurable composition was 4,000 microwatts/cmfi.

Example 118 916 g. (0.46mole) of a commercially available liquidpolymeric diisocyanate sold under the trade name Adiprene L-100 by E. I.du Pont de Nemonrs and Co. was charged to a dry flask maintained under anitrogen atmosphere and equipped with a condenser, stirrer, thermometerand gas inlet and outlet. 197 g. (0.92 mole) of the diallyl ether oftrimethylolpropane was charged to the vessel along with 0.56 g.dibutyltin dilaurate catalyst. The flask and contents were heated withstirring for 30 minutes at 50 C. to yield a polytetraene of about 2400M.W.

To the tetraene .was added 230 g. of pentaerythritol tetrakis(p-mercaptopropionate), 18.4 g. benzophenone, 1.2 g.dilaurylthio-dipropionate, 136 grams of dioctyl phthalate, and 1.2 g.Plastanox 2246 (hindered phenol antioxidant sold by American CyanarnidCo.). This photocurable liquid composition was cast on a glass plate ina layer mils thick. It was then exposed to UV radiation from a 275 WattType RS sunlamp. The intensity of the radiation incident on the surfaceof the layer was 3000 microwatts/cmF. The layer skin cured in about 1-2seconds and cured to a solid through the entire thickness in, less than20 seconds, or at a liquidto-solid conversionrate of over 120mils/minute. The solid rubbery product had a Shore Ahardness of 72, atensile strength of 150 psi. and an elongation at failure of 40 percent.

The solid cured .polythioether polymer products remolecular weight maybe calculated from the molecular weight of the reactants. p

The viscosity of the polyenes and polythiols may be measured on aBrookfield Viscometer at 30 or 70 C. in accord with the instructionstherefor.

The components to be cured may be prepared as either single-packaged ormulti-packaged liquid polymer systems which may be cured to solidpolythioether elasto mers without liberating gaseous by-products which,cause bubbles and voids in the vulcanizate. Thus, there isprovidedcurableliquid polymer systems composd of polyenesand polythiolsin which the components individually are storage stable and which arenot sensitive to or deteriorated by traces of moisture or oxygencontaining'gas such 'as may be encountered during normal storage orhandling procedures. Solid resinous or elastom'eric products may beprepared from flowable liquids in a system in which the rate of curingmay be inhibited or retarded by the use of chemical inhibitors,antioxidants, inert atmospheres and the like.'The cured product may becharacterized as in the thermally and oxidatively stable state sincethere is no reactive carbon-to-carbon unsaturation in the main backbonechain. 1

As used herein the term polyene and the term polyne refers to single orcomplex species of alkenes or alkyries having a multiplicity of terminalreactive carbon-to-carbon unsaturated functional groups per averagemolecule. For example, a diene is a polyene that has two reactivecarbon-to-carbon double bonds per average molecule, while a diyne is apolyyne that contains in its structure known two reactivecarbon-to-carbon triple bonds per average molecule. Combinations ofreactive double bonds and reactive triple bonds within the same moleculeare also possible such as for monovinylacetylene which is a polyeneyneunder this definition. For purposes of brevity all these classes ofcompounds are referred to hereafter as polyenes.

In defining the position of the reactive functional carbon-to-carbonunsaturation, the term terminal is intended to mean that functionalunsaturation is at an end of the main chain in the molecule; whereas bynear terminal is intended to mean that the functional unsaturation isnot more than 10 carbon atoms and typically less than 8 carbon atomsfrom an end of the main chain in the molecule.

The term pendant means that the reactive carbon-to-car bon unsaturationis located terminal or near-terminal in a branch of the main chain ascontrasted to a position at or near the ends of the main chain. Forpurposes of brevity all of these positions are referred to hereingenerally as terminal unsaturation.

Functionality as used herein refers to the average number of ene orthiol groups per molecule in the polyene or polythiol, respectively. Forexample a triene is a polyene with an average of three reactivecarbon-to-carbon unsaturated groups per molecule and thus has afunctionality (f) of three. A dithiol is a polythiol withan average oftwo thiol groups per molecule and thus has a functionality (f) of two.

It is to be understood that the functionality of the polyene and thepolythiol component is commonly expressed in whole numbers although inpractice the actual functionality may be fractional. For example, apolyene component having a nominal functionality of 2 (from theoreticalconsiderations alone) may in fact have an eifective functionality ofsomewhat less than 2. In an attempted synthesis of a diene from a glycolin which the reaction proceeds to 100% of the theoretical value forcomplete reaction, the functionality (assuming 100% pure startingmaterials) would be 2.0. If however, the reaction were carried to only90% of theory for complete reaction, about 10% of the molecules presentwould have only one ene functional group, and there may be a trace ofmaterial that would have no ene functional groups at all. Approximately90% of the molecules, however, would have the desired diene structureand the product as a whole then would have an actual functionality of1.9. Such a product is useful in the instant invention and is referredto herein as having a functionality of 2.

The term reactive unsaturated carbon-to-carbon groups means groups whichwill react under proper conditions as set forth herein with thiol groupsto yield the thioether as contrasted to the term unreactivecarbon-to-carbon unsaturation which means groups found in aromaticnucleii (cyclic structures exemplified by benzene, pyridine, anthracene,and the like) which do not under the same conditions react with thiolsto give thioether linkages.

Highly water-sensitive groups are intended to include, for example,isocyanate, acylhalide such as acylchloride, anhydride and the likewhich readily react with water, alcohols, ammonia, amines and the like.

Odorless has been used herein to mean the substantial absence of thewell-known offensive and sometimes obnoxious odors that arecharacteristic of hydrogen sulfide and the derivative family ofcompounds known as mercaptans.

The term non-yellowing means the substantial resistance during prolongedexposure to actinic radiation such as exposure in sunlight, to unsightlyor uncontrollable discoloration.

It is understood that the foregoing detailed description is given merelyby way of illustration and that many variations may be made thereinwithout departing from the spirit of this invention.

What is claimed is:

1. A photocurable composition useful for obtaining an essentiallyodorless, solid polythioether, said photocurable composition consistingessentially of:

(A) a terminally unsaturated polyene component which comprises theformula:

wherein m is an integer of at least 2; wherein X is R is a radicalselected from the group consisting of hydrogen, fluorine, chlorine,furyl, thienyl, pyridyl, phenyl and substituted phenyl, benzyl andsubstituted benzyl, alkyl and substituted alkyl, alkoxy and substitutedalkoxy, cycloalkyl and substituted cycloalkyl; said substituents on saidsubstituted members selected from the group consisting of nitro, chloro,fluoro, acetoxy, acetamide, phenyl, benzyl, alkyl, alkoxy andcycloalkyl; said alkyl and alkoxy having from 1 to 9 carbon atoms andsaid cycloalkyl having from 3 to 8 carbon atoms;

wherein:

[A] is free of reactive carbon-to-carbon unsaturation; free of highlywater-sensitive members; and is a polyvalent chemically compatiblemember of the group [consisting of carbonate, carboxylate, carbonyl,ether, silane, silicate, phosphonate, phosphite, phosphate, alkyl andsubstituted alkyl, cycloalkyl and substituted cycloalkyl, aryl andsubstituted aryl, urethane and substituted urethane, urea andsubstituted urea, amine and substituted amine, amide and substitutedamide, hydroxyl, heterocyclic carbon containing radical, and mixturesthereof; said substituents on said members substituted being definedabove, said component having a molecular weight in range from about 64to 20,000; and a viscosity in the range from essentially 0 to 20 millioncentipoises at 70 C.; and

(B) a polythiol component having a molecular weight in the range fromabout 50 to about 20,000 of the general formula:

wherein R is a polyvalent organic moiety free from reactivecarbon-to-carbon unsaturation and n is at least 2, the sum of m and nbeing greater than 4, with the ene/thiol mole ratio being selected so asto provide a cross-linked solid, self-supporting cured product; and

(C) a photocuring rate accelerator.

2. The composition of claim 1 wherein [A] has the formula:

a and b are integers greater than 1; R is a member of the groupconsisting of hydrogen and alkyl;

R is a'member of the group consisting of hydrogen,

and saturated alkyl;

R is a divalent derivative of the group consisting of phenyl, benzyl,alkyl, cycloalkyl, substituted phenyl,

40 carbon containing radical, and mixtures thereof; said substituents onsaid members substituted being defined above, said component having amolecular weight in the substituted benzyl, substituted alkyl andsubstituted 5 range from about 64 to 20,000; and a cycloalkyl, viscosityin the range from essentially 0 to said alkyl, cycloalkyl andsubstituents on members sub- 20 million centipoises at 70 C.;andstituted being'defined as in claim 1. (B) a polythiol componenthaving a molecular 3:. The composition of claim 1 wherein thephotocuring weight in the range from about 50 to abou rate acceleratoris a member selected from the group 20,000'0f the general formula!consisting of aryl aldehyde, diaryl ketone, alkyl aryl ketone, triarylphosphine, and a blend of carbontetra- L halide with polynucleararomatic hydrocarbon. n

4. The composition of claim 1 wherein the mole ratio of ene to thiol isfrom about 0.5/1 to about 2/1. Wherem 15 a lwllwtllmt 5. The compositionof claim 1 wherein the mole ratio P reactwe carbon'to'carbonunsahiratlon and of ene to thiol is from about 0.75/1 to about 1.5/1. nis at least. the sum of i and n bemg greafer 6. A process'of formingessentially odorless solid polythan wlth the ene/@1101 mole ,ratm belPgthioether which comprises selected was to provide a cross-lmked sohd,(I) Admixing: self-supportmgcured product; and (A) a terminallyunsaturated polyene component 2 Photocurmg rate accelerator there whichcomprises the formula (II) Exposing the mixture to actinic. light. w f7. The solid product prepared by the process ofclaim Pi 2' e a 8. Theprocess of claim 6 wherein the actinic light is wherein m i an integer fat least 2; h i ultraviolet radiation having a wavelength between aboutX is 2000 A. and about 4000 A. R R 9. The process of claim 6 whereinthecomposition con- & A} tams from 0.0005 to 50 parts by welght of aphotocuring rate accelerator. where, 10. The process of claim 6 whereinthe photocuring R is a radical selected from the group consistrateaccelerator is selected from the group consisting of ing of hydrogen,fluorine, chlorine, furyl, aryl aldehyde; diaryl ketone;alkyl arylketone; triaryl thienyl, pyridyl, phenyl and substituted phosphine; ablend ofcarbon tetrahalide with polynuclear phenyl, benzyl andsubstituted benzyl, alkyl aromatic hydrocarbon. and substituted alkyl,alkoxy and sub- 11. An article comprising the composition of claim 6stituted alkoxy, cycloalkyl and substituted as a coating ona substrate.I cycloalkyl; said substituents on said sub- 12. An article comprisingthe-composition of claim 6 stituted members selected from the group 40as an adhesive between two substrates. consisting of nitro, chloro,fluoro, acetoxy, 13. An article comprising, the composition of claim 6acetamide, phenyl, benzyl, alkyl, alkoxy as an elastomeric sealant. andcycloalkyl; said alkyl and alkoxy hav- 14. A shaped, molded article castfrom the composition ing from 1 to 9 carbon atoms and said cyof claim 6.I cloalkyl having from 3 to 8 carbon atoms; 15. The composition of claim1 wherein the polyene wherein has the formula:

OH: OH! 0 0 l CHz=CH-SCHzCHz0(i l'-NH NH-ii-o- {021140) (0on0) (canto) ik-NH Nno-o-l-cn,on, s g= [A] is free of reactive carbon-to-carbonunsaturation; free of highly water-sensitive members; and is apolyvalent chemically compatible member of the group consistingsubstituted amide, hydroxyl, heterocyclic 7 where the sum of x+y+z ineach .chain segment is at least 1; and n is an integer of O or greater.

16. The composition of claim 1 wherein the polyene has the formula: l n

TCHTEZHI where n is an integer of 0 or greater.

17. The composition of claim 1 wherein the polyene has the formula:

where n is an integer of 0 or greater.

(References on following page)

